Under cross examination by Louis P. Aloise, one of Ms. Corey's lawyers, Mr. Dion was asked the following question: “Isn't it a fact, Mr. Dion, that you knew exactly where that baby had come from?”

“No,” said Mr. Dion.

Mr. Dion then denied Mr. Aloise's suggestion that Roberto C. “Tito” Rodriguez, Ms. Haynes' former boyfriend, had turned the baby over to him and Ms. Corey.

Ms. Corey's lawyers acknowledge that she was found with Ms. Haynes' baby, but maintain she played no role in the slaying.

Mr. Dion, who was called to the stand in Worcester Superior Court as a prosecution witness at Ms. Corey's murder trial, testified earlier that he thought it odd when Ms. Corey called him on July 23, 2009, to say she was giving a pregnant Darlene Haynes a ride to the store.

“They weren't friends. They didn't hang out. It was not something she'd normally do,” Mr. Dion said. It struck him as unusual that Ms. Corey would be giving Ms. Haynes a ride, he said, because the two women were nothing more than acquaintances.

Mr. Dion said Ms. Corey, who he believed was also pregnant at the time, had borrowed his 1996 Ford Escort earlier in the day, telling him she was going to visit a friend in Marlboro, where she had grown up. After changing her “due date” several times, Ms. Corey had informed him that she was scheduled for a cesarean section the next day, according to Mr. Dion.

Assistant District Attorney Daniel J. Bennett showed Mr. Dion a surveillance videotape from Randell's Package Store on Canterbury Street that depicted Ms. Haynes arriving at the package store shortly after 8 on the night of July 23, 2009, making a purchase of two wine coolers and leaving in the car that Mr. Dion identified as his.

Prosecutors say Ms. Corey was the last person to be seen with Ms. Haynes before she was found dead in a closet in the bedroom of her apartment at 94 Southgate St. on July 27, 2009. Ms. Corey, 39, stands accused of murdering the 23-year-old woman, cutting her abdomen open, removing the baby girl she was carrying and trying to pass the newborn off as her own.

An autopsy determined that the victim died from multiple blunt trauma causing skull fractures, asphyxiation by an electrical cord that was found wrapped around her neck and a 9-inch incision in her abdomen. Her fetus and reproductive organs were missing when her body was discovered by her landlord.

No one else has been charged in the slaying.

Two days after Ms. Haynes' decomposing body was found, Ms. Corey and Mr. Dion showed up at a homeless shelter in Plymouth, N.H., with a newborn baby girl she claimed was hers. DNA testing later showed that Ms. Haynes was the biological mother of the child and Mr. Rodriguez, with whom the girl now lives, was the father.

Sometime around 11:30 p.m. on July 23, 2009, Mr. Dion said, he received another call from Ms. Corey telling him that her water had broken. He said he suggested she call for an ambulance, but she told him her friend was taking her to the hospital in Framingham.

A couple of hours later, Ms. Corey called him again to inform him “that we had a baby,” Mr. Dion testified. He said it was one of about a dozen calls he would receive from Ms. Corey over the next several hours. During one of their conversations, Ms. Corey said she was unhappy with the way the medical staff was treating her and the baby and wanted to leave the hospital, according to Mr. Dion.

In the course of another, “She said she was going to sign herself out against medical advice,” he testified.

Mr. Dion said Ms. Corey arrived home between 7 and 8 a.m. with the baby girl he believed was his daughter. The newborn had what appeared to be dried blood on her body and a piece of string tied around her umbilical cord, according to Mr. Dion.

He said he and Ms. Corey showed the baby off to family and friends over the next couple of days and then followed through on their plan to move to Ms. Corey's father's house in New Hampshire in hopes that Earl Corey Sr. would help him find work.

They ended up at the homeless shelter in Plymouth, N.H., he said, after Ms. Corey told him they could not stay at her father's house because there wasn't enough room.

Mr. Bennett suggested that phone records he showed to Mr. Dion indicated one of the calls he received from Ms. Corey on the morning of July 24 was made from Ms. Haynes' cell phone. The number in question was the one Ms. Haynes had listed as her own during one of her medical appointments, according to another document introduced into evidence.

During his cross-examination of Mr. Dion, Mr. Aloise showed him the same records and pointed out that the account was in the name of Mr. Rodriguez.